Complications from intraocular surgery, especially cataract surgery and pars plana vitrectomy, represent one of the most important causes of corneal edema and bullous keratopathy. The objective of this research proposal is to study the pathogenesis of corneal edema which develops following intraocular surgery. The first phase of this study will be to investigate the structural and functional changes in the corneal endothelium due to chemical trauma - pH variation, solution preservatives, ethylene oxide breakdown products, sulfur hexafluoride gas contaminants, radiation and changes in intraocular fluid composition following pars plana vitrectomy. A second phase of this investigation will study the role of membrane sulfhydryls in maintenance of endothelial barrier and pump functions. A third phase of this study will be concerned with evaluation of corneal endothelial structure and function in decompensated corneas with a decreased cell population, metabolic disease or increased intraocular pressure. In situ studies will be performed on rabbit and monkey eyes by injection of the various agents into the anterior chamber. Pars plana vitrectomy will be performed using a vitreous infusion suction cutter. Corneal changes will be evaluated by biomicroscopy and pachometry and the intraocular fluids analyzed. In vitro studies will be performed on isolated rabbit, monkey and human corneas perfused in the specular microscope. During the perfusion the physiological state of the corneal endothelium will be assessed by measuring changes in the following parameters: corneal thickness, metabolism, endothelial cell pattern, and endothelial permeability. These changes will be directly related to the ultrastructural appearance of the endothelial cells as studied by scanning and transmission electron microscopy.